The positioning of the Earth relative to the sun allows the Earth's northern hemisphere to bask in more direct sunlight on the summer solstice than on any other day of the year. With the sun so high, it is also the longest day of the year for every place north of the Tropic of Cancer.
The Met Office says: "At the summer solstice, the sun reaches its highest point of the year, while at the winter solstice, the noon sun is the lowest it will be all year". Last summer, the solstice came June 20, but it will come June 21 both of the next two summers.
Today is the first day of summer for the Central, Mountain and Pacific time zones along with Alaska and Hawaii.
From now until the Winter Solstice in December, the amount of daylight will shrink slowly each day.
In Seattle, the moment of the solstice comes at an opportune time: Summer officially begins at 9:24 p.m., just minutes after official sunset at 9:10. It's all part of the variation of seasons, which occurs because of Earth's tilt with respect to the sun.
Here are some facts to know about the first day of summer. According to the National Oceanic and Atmospheric Administration (NOAA), Northern Wisconsin will experience 15.5 to 16 hours of daylight.
You can join the City of Fruita in celebrating the extra hours of daylight on Wednesday, June 21st. That means a longer duration for sunset at the solstices.
Next year, the solstice will be on June 21.
Areas north of the Arctic circle receive sunlight for 24 hours during the summer solstice - while areas south of the Antarctic circle have a full day of darkness.